gl852 Genesys Logic, gl852 Datasheet - Page 19

• Manufacturer Part Number: gl852
• Description: Usb 2.0 Mtt Hub Controller
• Manufacturer: Genesys Logic

©2000-2007 Genesys Logic Inc. - All rights reserved.
GL852 internally contains a power on reset circuit. The power on sequence is depicted in the next picture.
To fully control the reset process of GL852, we suggest the reset time applied in the external reset circuit
should longer than that of the internal reset circuit.
To save pin count, GL852 uses the same pin to decide individual/gang mode as well as to output the
suspend flag. The individual/gang mode is decided within 20us after power on reset. Then, about 50ms later,
this pin is changed to output mode. GL852 outputs the suspend flag once it is globally suspended. For
individual mode, a pull low resister greater than 100K
resister which greater than 100K
indicator schematics. It should be noticed that the polarity of LED must be followed, otherwise the suspend
current will be over spec limitation (2.5mA).
5.2.2 PGANG/SUSPND Setting
Internal reset
External reset
Figure 5.3 - RESET# (External Reset) setting and application
Figure 5.4 - Power on sequence of GL852
≒
2.7
Power good voltage, 2.5~2.8V
μ
should be placed. In figure 5.6, we also depict the suspend LED
s
should be placed. For gang mode, a pull high
GL852 USB 2.0 MTT HUB Controller
VCC(3.3V)
Page 19